A central processing unit (CPU) may consume a significant amount of power during operation. Some conventional systems provide for operation of CPUs in one or more selectable performance states. For example, a CPU may be selectively controlled to operate at a first frequency and a first voltage (i.e., a first performance state) or at a higher frequency and higher voltage (i.e., a second performance state). The CPU may therefore consume less power in the first performance state than in the second performance state.
Determination of a CPU performance state is typically based only on a percentage utilization of the CPU. The CPU may be controlled to operate in a low performance state if the percentage utilization is below a threshold level, and in a higher performance state if the percentage utilization is above a threshold level. Systems that may provide more efficient operation are desirable.